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package com.sun.corba.se.impl.encoding;

import com.sun.corba.se.spi.ior.iiop.GIOPVersion;
import com.sun.corba.se.impl.orbutil.ORBConstants;

public class CDRInputStream_1_2 extends CDRInputStream_1_1 {

  // Indicates whether the header is padded. In GIOP 1.2 and above,
  // the body must be aligned on an 8-octet boundary, and so the header is
  // padded appropriately. However, if there is no body to a request or reply
  // message, there is no header padding, in the unfragmented case.
  protected boolean headerPadding;

  // used to remember headerPadding flag when mark() and restore() are used.
  protected boolean restoreHeaderPadding;

  // Called by RequestMessage_1_2 or ReplyMessage_1_2 classes only.
  void setHeaderPadding(boolean headerPadding) {
    this.headerPadding = headerPadding;
  }

  // the mark and reset methods have been overridden to remember the
  // headerPadding flag.

  public void mark(int readlimit) {
    super.mark(readlimit);
    restoreHeaderPadding = headerPadding;
  }

  public void reset() {
    super.reset();
    headerPadding = restoreHeaderPadding;
    restoreHeaderPadding = false;
  }

  // Template method
  // This method has been overriden to ensure that the duplicated stream
  // inherits the headerPadding flag, in case of GIOP 1.2 and above, streams.
  public CDRInputStreamBase dup() {
    CDRInputStreamBase result = super.dup();
    ((CDRInputStream_1_2) result).headerPadding = this.headerPadding;
    return result;
  }

  protected void alignAndCheck(int align, int n) {

    // headerPadding bit is set by read method of the RequestMessage_1_2
    // or ReplyMessage_1_2 classes. When set, the very first body read
    // operation (from the stub code) would trigger an alignAndCheck
    // method call, that would in turn skip the header padding that was
    // inserted during the earlier write operation by the sender. The
    // padding ensures that the body is aligned on an 8-octet boundary,
    // for GIOP versions 1.2 and beyond.
    if (headerPadding == true) {
      headerPadding = false;
      alignOnBoundary(ORBConstants.GIOP_12_MSG_BODY_ALIGNMENT);
    }

    checkBlockLength(align, n);

    // WARNING: Must compute real alignment after calling
    // checkBlockLength since it may move the position

    // In GIOP 1.2, a fragment may end with some alignment
    // padding (which leads to all fragments ending perfectly
    // on evenly divisible 8 byte boundaries).  A new fragment
    // never requires alignment with the header since it ends
    // on an 8 byte boundary.

    int alignIncr = computeAlignment(bbwi.position(), align);
    bbwi.position(bbwi.position() + alignIncr);

    if (bbwi.position() + n > bbwi.buflen) {
      grow(1, n);
    }
  }

  public GIOPVersion getGIOPVersion() {
    return GIOPVersion.V1_2;
  }

  public char read_wchar() {
    // In GIOP 1.2, a wchar is encoded as an unsigned octet length
    // followed by the octets of the converted wchar.
    int numBytes = read_octet();

    char[] result = getConvertedChars(numBytes, getWCharConverter());

    // Did the provided bytes convert to more than one
    // character?  This may come up as more unicode values are
    // assigned, and a single 16 bit Java char isn't enough.
    // Better to use strings for i18n purposes.
    if (getWCharConverter().getNumChars() > 1) {
      throw wrapper.btcResultMoreThanOneChar();
    }

    return result[0];
  }

  public String read_wstring() {
    // In GIOP 1.2, wstrings are not terminated by a null.  The
    // length is the number of octets in the converted format.
    // A zero length string is represented with the 4 byte length
    // value of 0.

    int len = read_long();

    //
    // IMPORTANT: Do not replace 'new String("")' with "", it may result
    // in a Serialization bug (See serialization.zerolengthstring) and
    // bug id: 4728756 for details
    if (len == 0) {
      return new String("");
    }

    checkForNegativeLength(len);

    return new String(getConvertedChars(len, getWCharConverter()),
        0,
        getWCharConverter().getNumChars());
  }
}
